Intended for healthcare professionals

Rapid response to:


Proposals to increase the motorway speed limit by 10 mph

BMJ 2012; 344 doi: (Published 05 January 2012) Cite this as: BMJ 2012;344:d7790

Rapid Response:

Re: Proposals to increase the motorway speed limit by 10 mph

I believe that both M. A. James and C. K. Connolly present dubious cases for easing motorway speed limits.

First, unlimited speed as a sensible means of reducing bunching: this ignores the increase of intervehicular distance concomitant on each vehicle's increased kinetic energy - a function of the square of speed - if collision is to be avoidable.

Second, the argument that a "maximum safe speed" is "fundamentally flawed" is highly dubious. On the railways, speed is carefully controlled, and it can be argued that the same should apply to the road.

It is alway astonishing that "society" expects perfect safety for the railways, but is mostly insensitive to the casualty levels on the roads - including motorways. Witness the attention officially expended on the Pendolino derailment on the West-Coast mainline with its single fatality a year or two back.

How often does a motorway crash entailing a single fatality receive anything beyond a brief mention in the local media - let alone an enquiry?

Competing interests: No competing interests

17 March 2012
Tony H. Reinhardt-Rutland
Reader in Psychology
University of Ulster
Coleraine BT52 1SA